1. Field of Invention
This invention relates to a low profile baseframe for use with a desk or other support, the baseframe having ball races integrally formed along each side and to a method of construction of a low profile baseframe. This invention further relates to ball retainers that are sized and shaped to fit within the ball races so that rows of ballbearings in each retainer are substantially vertical relative to one another.
2. Description of the Prior Art
It is known to have a baseframe with an outer frame and a ball race affixed to the outer frame along each side of the outer frame by rivets or by other fasteners. Each ball race contains a ball retainer that is mounted in the ball race. The ball retainer supports two rows of ballbearings that are substantially vertical relative to one another when the baseframe is in use. The height of the baseframe is greater than the height of the ball retainers. When the baseframe is used to slidably support a computer peripheral such as a keyboard, the overall height is important. If the overall height is too high and the baseframe is mounted beneath a desktop, the baseframe and peripheral can interfere with the use of the desk by a user when the baseframe is in the stored position and when the baseframe is in use. When the two rows of ballbearings are substantially vertical relative to one another, the ball retainer is referred to as being vertical. Previous baseframes with vertical ball retainers have an overall height of approximately 1.5 inches.
It is also known to have a baseframe where the ball retainers are oriented so that the rows of ballbearings are horizontal relative to one another. These are referred to as horizontal ball retainers. (See Timm U.S. Pat. No. 6,450,467. The ball retainers are affixed to the outer frame in an orientation where the two rows of ballbearings are horizontal relative to one another). In this orientation, the ball retainers open towards the top and a lower overall height is achieved because the horizontal ball retainers have lesser height than vertical ball retainers of the same size. However, a slide plate extending between the two horizontal ball retainers must be shaped to connect to a bracket extending between the two rows from the top, which increases the height of the baseframe. Also, the slide plate does not operate as smoothly as it does when the rows of ballbearings are vertical as the ball retainers are designed for vertical orientation with two single point contacts for each ballbearing. Both rows of ballbearings are located beneath the slide plate. In FIG. 11 of the Timm Patent, the slide plate is not flat and has two Z-shaped brackets affixed along each retainer. The brackets connect to another bracket that contacts each row of bearings. The overall height achieved by the baseframe described in the Timm Patent is said to be 0.75 inches. The horizontal ball retainers result in a wider baseframe than previous baseframes with vertical ball retainers.